*Choose Index below for a list of all words and phrases defined in this glossary.*

**T-Test** - A method to assess whether the means of two groups are statistically different from each other.

[Category=Quality ]

*Source: American Society for Quality, 27 October 2010 08:34:13, http://www.asq.org/glossary/ *

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**t Test **- The t test employs the statistic (t), with n-1 degrees of freedom, to test a given statistical hypothesis about a population parameter. Usually used with small sample sizes (<30). It is used when population standard deviation is unknown.

[Category=Data Quality ]

**T-test **- A t-test is a statistical tool used to determine whether a significant difference exists between the means of two distributions or the mean of one distribution and a target value.

[Category=Data Quality ]

*Source: iSixSigma, 27 February 2011 10:44:31, https: web.archive.org/web/20111109014246/http:www.isixsigma.com/index.php?option=com_glossary *

**t-test **- used to test means or location effects. For example, used to compare the mean output of Line A vs. the mean output of Line B. [Statistical inference tests to compare the Quality_ of different products / processes and compare the performance of different groups.]

[Category=Quality ]

*Source: The Quality Portal, 28 April 2011 08:41:21, http://thequalityportal.com/glossary/s.htm *

Data Quality Glossary. A free resource from GRC Data Intelligence. For comments, questions or feedback: dqglossary@grcdi.nl